linux-toradex.git/kernel/sched/rt.c, branch v5.12-rc5

sched: Use task_current() instead of 'rq->curr == p'

2021-01-14T10:20:11+00:00

Use the task_current() function where appropriate.

No functional change.

Signed-off-by: Hui Su 
Signed-off-by: Peter Zijlstra (Intel) 
Reviewed-by: Steven Rostedt (VMware) 
Link: https://lkml.kernel.org/r/20201030173223.GA52339@rlk

sched: Remove select_task_rq()'s sd_flag parameter

2020-11-10T17:39:06+00:00

Only select_task_rq_fair() uses that parameter to do an actual domain
search, other classes only care about what kind of wakeup is happening
(fork, exec, or "regular") and thus just translate the flag into a wakeup
type.

WF_TTWU and WF_EXEC have just been added, use these along with WF_FORK to
encode the wakeup types we care about. For select_task_rq_fair(), we can
simply use the shiny new WF_flag : SD_flag mapping.

Signed-off-by: Valentin Schneider 
Signed-off-by: Peter Zijlstra (Intel) 
Link: https://lkml.kernel.org/r/20201102184514.2733-3-valentin.schneider@arm.com

Merge branch 'sched/migrate-disable'

2020-11-10T17:39:04+00:00

sched: Fix migrate_disable() vs rt/dl balancing

2020-11-10T17:39:01+00:00

In order to minimize the interference of migrate_disable() on lower
priority tasks, which can be deprived of runtime due to being stuck
below a higher priority task. Teach the RT/DL balancers to push away
these higher priority tasks when a lower priority task gets selected
to run on a freshly demoted CPU (pull).

This adds migration interference to the higher priority task, but
restores bandwidth to system that would otherwise be irrevocably lost.
Without this it would be possible to have all tasks on the system
stuck on a single CPU, each task preempted in a migrate_disable()
section with a single high priority task running.

This way we can still approximate running the M highest priority tasks
on the system.

Migrating the top task away is (ofcourse) still subject to
migrate_disable() too, which means the lower task is subject to an
interference equivalent to the worst case migrate_disable() section.

Signed-off-by: Peter Zijlstra (Intel) 
Reviewed-by: Daniel Bristot de Oliveira 
Link: https://lkml.kernel.org/r/20201023102347.499155098@infradead.org

sched,rt: Use the full cpumask for balancing

2020-11-10T17:39:00+00:00

We want migrate_disable() tasks to get PULLs in order for them to PUSH
away the higher priority task.

Signed-off-by: Peter Zijlstra (Intel) 
Reviewed-by: Valentin Schneider 
Reviewed-by: Daniel Bristot de Oliveira 
Link: https://lkml.kernel.org/r/20201023102347.310519774@infradead.org

sched,rt: Use cpumask_any*_distribute()

2020-11-10T17:39:00+00:00

Replace a bunch of cpumask_any*() instances with
cpumask_any*_distribute(), by injecting this little bit of random in
cpu selection, we reduce the chance two competing balance operations
working off the same lowest_mask pick the same CPU.

Signed-off-by: Peter Zijlstra (Intel) 
Reviewed-by: Valentin Schneider 
Reviewed-by: Daniel Bristot de Oliveira 
Link: https://lkml.kernel.org/r/20201023102347.190759694@infradead.org

sched: Fix hotplug vs CPU bandwidth control

2020-11-10T17:38:59+00:00

Since we now migrate tasks away before DYING, we should also move
bandwidth unthrottle, otherwise we can gain tasks from unthrottle
after we expect all tasks to be gone already.

Also; it looks like the RT balancers don't respect cpu_active() and
instead rely on rq->online in part, complete this. This too requires
we do set_rq_offline() earlier to match the cpu_active() semantics.
(The bigger patch is to convert RT to cpu_active() entirely)

Since set_rq_online() is called from sched_cpu_activate(), place
set_rq_offline() in sched_cpu_deactivate().

Signed-off-by: Peter Zijlstra (Intel) 
Reviewed-by: Valentin Schneider 
Reviewed-by: Daniel Bristot de Oliveira 
Link: https://lkml.kernel.org/r/20201023102346.639538965@infradead.org

sched: Remove relyance on STRUCT_ALIGNMENT

2020-10-29T10:00:32+00:00

Florian reported that all of kernel/sched/ is rebuild when
CONFIG_BLK_DEV_INITRD is changed, which, while not a bug is
unexpected. This is due to us including vmlinux.lds.h.

Jakub explained that the problem is that we put the alignment
requirement on the type instead of on a variable. Type alignment is a
minimum, the compiler is free to pick any larger alignment for a
specific instance of the type (eg. the variable).

So force the type alignment on all individual variable definitions and
remove the undesired dependency on vmlinux.lds.h.

Fixes: 85c2ce9104eb ("sched, vmlinux.lds: Increase STRUCT_ALIGNMENT to 64 bytes for GCC-4.9")
Reported-by: Florian Fainelli 
Suggested-by: Jakub Jelinek 
Signed-off-by: Peter Zijlstra (Intel)

sched/cpupri: Remap CPUPRI_NORMAL to MAX_RT_PRIO-1

2020-10-29T10:00:30+00:00

This makes the mapping continuous and frees up 100 for other usage.

Prev mapping:

p->rt_priority   p->prio   newpri   cpupri

                               -1       -1 (CPUPRI_INVALID)

                              100        0 (CPUPRI_NORMAL)

             1        98       98        1
           ...
            49        50       50       49
            50        49       49       50
           ...
            99         0        0       99

New mapping:

p->rt_priority   p->prio   newpri   cpupri

                               -1       -1 (CPUPRI_INVALID)

                               99        0 (CPUPRI_NORMAL)

             1        98       98        1
           ...
            49        50       50       49
            50        49       49       50
           ...
            99         0        0       99

Signed-off-by: Peter Zijlstra (Intel) 
Reviewed-by: Dietmar Eggemann

treewide: Convert macro and uses of section(foo) to section("foo")

2020-10-25T21:51:49+00:00

Use a more generic form for __section that requires quotes to avoid
complications with clang and gcc differences.

Remove the quote operator # from compiler_attributes.h __section macro.

Convert all unquoted __section(foo) uses to quoted __section("foo").
Also convert __attribute__((section("foo"))) uses to __section("foo")
even if the __attribute__ has multiple list entry forms.

Conversion done using the script at:

    https://lore.kernel.org/lkml/75393e5ddc272dc7403de74d645e6c6e0f4e70eb.camel@perches.com/2-convert_section.pl

Signed-off-by: Joe Perches 
Reviewed-by: Nick Desaulniers 
Reviewed-by: Miguel Ojeda 
Signed-off-by: Linus Torvalds